| Equipe(s) | Responsable(s) | Salle | Adresse |
|---|---|---|---|
| Combinatoire et Optimisation |
Jérémie Bouttier, Marco Mazzola, Sofia Tarricone |
15.16-413 | Campus Pierre et Marie Curie |
The purpose of this seminar is to foster exchanges within the CO team of IMJ-PRG, and also with the surrounding scientific community. As such, its range of topics should be quite broad. We initially plan one or two sessions per month.
Ce séminaire a pour but de développer les échanges au sein de l'équipe Combinatoire et Optimisation, et avec la communauté scientifique environnante. Ses thèmes seront donc larges. Nous prévoyons un rythme initial de une à deux séances par mois.
| Orateur(s) | Titre | Date | Début | Salle | Adresse | Diffusion | ||
|---|---|---|---|---|---|---|---|---|
| + | Jimmy Lamboley | Stabilité pour l'inégalité de Talenti | 17/10/2025 | 11:00 | 15.16-413 | Campus Pierre et Marie Curie | ||
Dans cet exposé, on présentera la notion de symétrisation de Schwarz, classique en calcul de variation, et en particulier l’inégalité de Talenti sur le comportement de cette symétrisation pour le problème de Dirichlet. Ensuite on présentera l’inégalité isopérimétrique quantitative de [Fusco-Maggi-Pratelli 2008] et ses différentes stratégies de démonstration. Enfin on réunira ces deux parties préliminaires pour expliquer comment on vise à obtenir des inégalités de Talenti quantitative avec exposant optimal. |
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| Orateur(s) | Titre | Date | Début | Salle | Adresse | ||
|---|---|---|---|---|---|---|---|
| + | Sylvie Corteel | Introduction à la combinatoire intégrable | 19/09/2025 | 11:00 | 15-16 413 | ||
Cet exposé sera un exposé introductif à la combinatoire intégrable et en particulier aux systèmes de particules, aux pavages et aux modèles de vertex et leur lien avec les fonctions symétriques. Le but de cet exposé est d'être pédagogique et ne demande pas de prérequis sur le sujet. |
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| + | Elsa Marchini | Optimally Controlled Moving Sets with Geographical Constraints | 27/06/2025 | 14:00 | 15-16 101 | ||
The talk is concerned with a family of geometric evolution problems, modeling the spatial control of an invasive population within a plane region bounded by geographical barriers. The "contaminated region" is a set moving in the plane, which we would like to shrink as much as possible. To control the evolution of this set, we assign the velocity in the inward normal direction at every boundary point. Three main problems are studied: existence of an admissible strategy which eradicates the contamination in finite time, optimal strategies that achieve eradication in minimum time, strategies that minimize the average area of the contaminated set on a given time interval. For these optimization problems, a sufficient condition for optimality is proved, together with several necessary conditions. Based on these conditions, optimal set-valued motions are explicitly constructed in a number of cases. |
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| + | Karim Adiprasito | Combinatorics and Hodge theory: Interactions and applications (online) | 22/05/2025 | 14:00 | 15-16 413 | ||
I will discuss some of the beautiful and fruitful interactions between combinatorics and Hodge Theory, from McMullen's work on polytope algebras, to tropical geometry and matroids (and work with Björner and Huh-Katz), to recent work with Papadakis and Petrotou. [Due to unforeseen circumstances the talk will be given online on Zoom, it will be broadcast in the planned seminar room, you may also ask one of the organizers for the link.] |
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| + | David Hernandez | Combinatorics of cluster algebras and representations of quantum groups | 10/04/2025 | 14:00 | 15-16 413 | ||
We discuss applications of cluster structures in the representation theory of quantum groups. Such combinatorial structures capture some of the essence of tensor categories of representations. For instance, cluster structures allow to establish useful isomorphisms of Grothendieck rings between quantum affine algebras which are Langlands dual. |
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| + | Sylvain Sorin | No regret procedures | 06/03/2025 | 14:00 | 15-16 413 | ||
We study the implications of the « no-regret property » for procedures in continuous and discrete time used in on-line learning, game theory dynamics and convex optimization. We will recall the origin of the problem and describe several ramifications (calibration, variational inequalities). |
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